System, apparatus and method for sequencing objects having rfid tags on a moving conveyor

ABSTRACT

In some embodiments, apparatuses and methods are provided herein useful to track objects on a moving conveyor system. In some embodiments, an RFID based tracking system comprises a conveyor system to move and transport objects along a conveyance path, wherein each object includes a near field only RFID tag associated therewith and identifying the object. Each near field only RFID tag is not coupled to a far field antenna such that it is not readable in a far field of RFID communication and communicates only in a near field of RFID communication. An RFID tag reader is positioned to attempt to read the near field only RFID tag of each object. And a control circuit processes reads of the near field only RFID tags by the first RFID reader to determine an order of the objects being conveyed.

RELATED APPLICATION(S)

This application claims the benefit of U.S. Provisional Application No.62/098,576, filed Dec. 31, 2014, which is incorporated by reference inits entirety.

TECHNICAL FIELD

This invention relates generally to the sequencing of objects travelingon a moving conveyor system.

BACKGROUND

In retail distribution centers, boxes of goods are transported on amoving conveyor for routing to various locations in the center. It isdesired to sequence the order of the boxes traveling on the conveyor.Known approaches include positioning optically readable patterns on theboxes and optically reading the boxes as they pass an imager. Suchimagers represent a significant expense to the distributor. Otherapproaches involve the use of radio frequency identification (RFID) tagson the boxes which are read by RFID tag readers. However, the principlechallenge for using RFID technology on a conveyor is identifying thesequence order of the boxes on the conveyor. The boxes on a conveyor arefilled with various types of content. One box may have tissue paper andanother one shampoo. The tag attached to the tissue paper box willrespond to an RFID reader at greater distances than the tag attached tothe box of shampoo. The consequence of this is that the tag on thetissue box will likely read before the tag on the shampoo box. Thereader will think that the tissue box is in front of the shampoo boxeven though it is actually behind. All efforts to solve this with phaseshift, RSSI, and the like calculations have failed to provide anaccurate and reliable sequencing capability. The principle problem withthese solutions is that they struggle with the unpredictability of thepath that RF energy follows when it is reflected off the surfaces of thestructures in the facility.

BRIEF DESCRIPTION OF THE DRAWINGS

Disclosed herein are embodiments of systems, apparatuses and methodspertaining to the use of RFID technologies to track objects traveling ona conveyor (or other moving pathway). This description includesdrawings, wherein:

FIG. 1 is an illustration of a near field and a far field of RFIDcommunication in accordance with some embodiments.

FIGS. 2A-2D are illustrations of near field only RFID devices inaccordance with several embodiments.

FIG. 3 is a side view diagram of a radio frequency identification (RFID)based object tracking system for a moving conveyor in accordance withseveral embodiments.

FIG. 4 is a side view diagram of another RFID based object trackingsystem for a moving conveyor in accordance with several embodiments.

FIG. 5 is a side view diagram of another RFID based object trackingsystem for a moving conveyor in accordance with several embodiments.

FIG. 6 is a top down view of the system of FIG. 5 in accordance withseveral embodiments.

FIG. 7 is a functional block diagram in accordance with someembodiments.

FIG. 8 is a flow diagram of a method in accordance with severalembodiments.

Elements in the figures are illustrated for simplicity and clarity andhave not necessarily been drawn to scale. For example, the dimensionsand/or relative positioning of some of the elements in the figures maybe exaggerated relative to other elements to help to improveunderstanding of various embodiments of the present invention. Also,common but well-understood elements that are useful or necessary in acommercially feasible embodiment are often not depicted in order tofacilitate a less obstructed view of these various embodiments of thepresent invention. Certain actions and/or steps may be described ordepicted in a particular order of occurrence while those skilled in theart will understand that such specificity with respect to sequence isnot actually required. The terms and expressions used herein have theordinary technical meaning as is accorded to such terms and expressionsby persons skilled in the technical field as set forth above exceptwhere different specific meanings have otherwise been set forth herein.

DETAILED DESCRIPTION

Generally speaking, pursuant to various embodiments, systems,apparatuses and methods are provided herein useful to track, e.g.,sequence, objects moving on a conveyor or moving pathway using RFIDtechnologies. In some embodiments, a RFID based tracking systemincludes: a conveyor system configured to move and transport a pluralityof objects along a conveyance path, wherein each of the plurality ofobjects includes a near field only RFID tag associated therewith andidentifying the object, wherein each near field only RFID tag is notcoupled to a far field antenna such that it is not readable in a farfield of RFID communication and communicates only in a near field ofRFID communication; a first RFID tag reader positioned relative to afirst portion of the conveyor system and configured to attempt to readthe near field only RFID tag of each of the plurality of objects; and acontrol circuit configured to process reads of the plurality of nearfield only RFID tags by the first RFID reader to determine an order ofthe plurality of objects being conveyed.

In some embodiments, RFID-based object tracking systems use near fieldonly RFID tags such as the near field only RFID tags described in U.S.Pat. No. 8,286,884 issued Oct. 16, 2012 (Docket 98082); U.S. Pat. No.8,544,758 issued Oct. 1, 2013 (Docket 103529); U.S. Pat. No. 8,857,724issued Oct. 14, 2014 (Docket 130347); U.S. Pat. No. 8,286,887 issuedOct. 16, 2012 (Docket 98183); and U.S. Pat. No. 8,505,829 issued Aug.13, 2013 (Docket 130528), all of which are incorporated herein byreference. In these patents, a near field only RFID tag is an RFID tagthat does not include any far field components. Thus, the near fieldonly RFID, the tag is readable by an RFID tag reader in the near fieldof RFID communication but not in the far field of RFID communication. Insome embodiments, the near field portion of the RFID tag is apre-manufactured generic component which may be cooperated with a farfield antenna separately designed and manufactured for the application.

As is well known in the art, referring initially to FIG. 1, embodimentsof the near field and the far field of RFID communication are explainedand illustrated. For example, the near field is the region about theantenna of the reader 108 where the antenna and the tag 110 are coupledwithin one full wavelength of the carrier wave; however, in manypractical applications, the near field is within one half wavelength ofthe carrier wave. The far field 102 is the region beyond the near fieldregion, i.e., coupled beyond one full wavelength of the carrier wave. Inthe far field, electric and magnetic fields propagate outward as anelectromagnetic wave and are perpendicular to each other and thedirection of propagation. The angular field distribution does not dependon the distance from the antenna. These electric and magnetic fields arerelated to each other via free-space impedance. Thus, in the far fieldregion, the electromagnetic signal propagates as waveform.

In the near field region, the electromagnetic signal does not propagateas a waveform. The near field region has two sub-regions: a near fieldradiating sub-region 104 and a near field reactive sub-region 106. Inthe near field reactive sub-region 106, energy is stored, but notradiated. The near field reactive sub-region 106 is typically where thereader antenna and the tag are coupled within ½ wavelength of thecarrier wave. This is typically very close to the reader antenna. Thenear field radiating sub-region 104 is a transitional region between thenear field reactive sub-region 106 and the far field region 102. Thenear field radiating sub-region 104 is typically where the readerantenna and the tag are coupled between ½ to 1 full wavelength of thecarrier wave. In the near field radiating sub-region 104, while there isradiated electric and magnetic fields, these electric and magneticfields do not propagate and are not perpendicular to each other and tothe direction of propagation (if there were propagation). This is wellunderstood in the art.

In many embodiments, the boundary between the near field region and thefar field region can be defined as “r”, illustrated in FIG. 1. In someembodiments, this boundary is a function of the antenna characteristics(e.g., the antenna's electrical size) and the wavelengths used, as wellas whether the reader is a point source or array. In some embodiments,with antennas whose size is comparable to wavelength (such as commonlyused in UHF RFID applications), the approximate boundary (r) between thefar field and the near field regions may be expressed as r=2D²/λ where Dis the maximum antenna dimension and λ is the wavelength. Forelectrically small antennas (e.g., as used in LF/HF RFID applications),the near field radiating sub-region is small and the boundary r betweennear and far fields may be expressed as r=λ/2π. These relationships arewell known in the art.

Generally, the near field and far fields of RFID communication are wellknown in the art. Many near field devices include devices complying withthe Near Field Communication (NFC) Forum standards, High Frequency (HF)devices, Electronic Shelf Labels (ESLs), and so on. Other examples ofdevices that communicate in the near field are near field only tags suchas those tags described in U.S. Pat. No. 8,286,884 and U.S. Pat. No.8,286,887, both of which are incorporated herein by reference, i.e.,tags that lack a far field antenna and magnetically, inductively orcapacitively couple to a corresponding reader. Devices that communicatein the near field typically have a range of being detected at about aninch or so away up to about 1-2 feet maximum depending on thefrequencies used.

In a typical ultra-high frequency (UHF) RFID system where the carrierfrequency is in the range of 860-960 MHz, the effective near field isthe region up to approximately 1-15 centimeters from the reader antenna,whereas the far field is the region from approximately 15-40 centimetersand beyond the reader antenna. In many cases, the reader 108 can readtags in the near field up to about 15 centimeters away, depending on thetag antenna, the reader can read tags in the far field up to about 20-30feet or more away. These features are also well known in the art.

It is understood that the near field tags may be designed to operatewith reader antennas operating at a variety of frequencies, such as lowfrequency (LF) at 125-134 kHz, high frequency (HF) at 13.56 MHz, ultrahigh frequency (UHF) at 860-960 MHz, microwave frequencies at 2.4 and5.8 GHz, for example.

Another way to view near field and far field communications relates tohow the reader 108 and the tag 110 are coupled together. The reader anda near field tag communicate through magnetic, inductive or capacitivecoupling between the reader antenna and the tag antenna (typically anear field loop antenna). For example, a current is induced in thereader antenna (e.g., loop antenna), which when brought into close rangewith the tag antenna (loop antenna) induces a current in the tag antennawhich is modulated according to the data of the tag and induced back tothe reader antenna. This type of near field communication is well knownin the art and may be considered the near field reactive sub-region 106of FIG. 1. Devices capable of communicating in the near field radiatingsub-region need more than a loop antenna. For example, at least someadditional conducting portion extending from the loop antenna (such asthe conductors 214 and 216 of FIG. 2D discussed below). Such conductorswill provide some radiation of the electric and magnetic fields but notprovide a propagation of a waveform. This type of near fieldcommunication is well known in the art and may be considered the nearfield radiating sub-region 104 of FIG. 1.

With far field RFID devices, the reader 108 and the tag 110 communicatethrough the transmission of electromagnetic energy from the reader tothe tag which is reflected back as transmitted electromagnetic energy tothe reader. Far field communicating devices typically use dipoleantennas or other antenna structures capable of transmitting energy andreceived transmitted energy in the far field. In many cases, the farfield radiation decays as described in the far field region 102 ofFIG. 1. This type of far field communication is well known in the art.Further information regarding the near field and far fields of RFIDoperation are described in NIKITIN ET AL., “An Overview of Near FieldUHF RFID”, IEEE, February 2007, which is incorporated herein byreference.

It is noted that in some embodiments, the read range of a given readermay be limited or changed by reducing or adjusting the power level ofsignals transmitted by the RFID reader. For example, far field RFIDreaders at normal operating power levels may be able to read far fieldRFID tags up to 20-30 feet. For example, the transmit power of thereader could be adjusted such that the reader can only read RFID tags atless than the normal range, e.g., up to 10-20 feet. This allows for thereading of the tag to occur only when the tag and tag reader are broughtinto a closer proximity compared to when the reader reads at normalpower levels. Conversely, the increase of the read range results in thedetection of a less precise (farther) location relationship between thereader and the tag than when the RFID reader operates at normal power.

Some embodiments of the RFID-based object tracking system describedherein make use of near field only RFID tags. Several examples of nearfield only RFID tags are described next. FIG. 2A illustrates a nearfield only RFID tag 200 including an integrated circuit 204 (or chip204) and a loop 202 formed on a substrate 206, but does not include afar field antenna. In some embodiments, the near field only RFID tag 200may be formed by removing the far field antenna or may bepre-manufactured to not include the far field antenna. The near fieldonly RFID tag 200 does not function as a far field RFID tag, i.e., onits own, it cannot be read in the far field by a tag reader. In someembodiments, the near field RFID tag 200 may be implemented as theImpinj® Button™ (commercially available from Impinj, Inc. of Seattle,Wash.) which is a near field only tag that has a chip with a circularloop antenna (and no patterned elongated conductors), which on its ownonly allows for communication in the near field reactive sub-region 106.

Other suitable near field only RFID tags may be designed to be coupledto a far field antenna such that the coupled device operates in the nearfield and far field of RFID communication. For example, the loop antennais designed, shaped and/or configured to be suitable for use for with afar field antenna to be electromagnetically and/or electrically coupledthereto. In one example, FIG. 2B shows a near field only RFID tag 205including an integrated circuit chip 204 formed on a substrate 206 andincluding a coupling conductor 208 that will assist in coupling the nearfield only RFID tag 205 with a far field antenna. This embodiment issimilar to the near field only RFID tag 200 of FIG. 2A, but includes thecoupling conductor 208. The coupling conductor may extend from the loop202 in a variety of ways and have varying lengths depending on the farfield antenna to be coupled therewith. However, the coupling conductor208 does not itself function as a far field antenna. Accordingly, whilethere is some additional conductive material apart from the loop 202(i.e., the coupling conductor 208), on its own, the near field only RFIDtag 205 is only readable in the near field. However, if coupled to a farfield antenna, the resulting combination functions in both the nearfield and the far field.

In another example, FIG. 2C shows a near field only RFID tag 215including the integrated circuit 204 (chip 204), the loop 202 andconductors 210 and 212 formed on the substrate 206 to allow forcapacitive coupling with a far field antenna according to anotherembodiment. In operation, each of the conductors 210 and 212 canfunction as a first electrode of a capacitor formed between itself and afar field or tag antenna, where a portion of the far field antenna formsthe second electrode of the capacitor. Like the device of FIG. 2B, whilethere is some additional conductive material apart from the loop 202(i.e., the conductors 210 and 212), on its own, the near field only RFIDtag 215 is only readable in the near field.

In a further example, FIG. 2D illustrates a near field only RFID tag 225that includes the integrated circuit or chip 204 coupled to the nearfield antenna 202 (e.g., loop antenna) and including elongatedconductors 214 and 216 that allow the loop antenna 202 to be coupled toa far field antenna. In some embodiments, the near field only RFID tag225 may be implemented as the Impinj® Bolt™ (commercially available fromImpinj, Inc. of Seattle, Wash.) which is a near field only tag that hasa chip with a loop antenna and patterned elongated conductors to allowfor capacitive coupling of the loop to a far field antenna. It is notedthat the loop antenna 202 allows for communication in the near fieldreactive sub-region 106, and the conductors 214 and 216 allow forcommunication in the near field radiating sub-region 104. Like thedevices of FIGS. 2B and 2C, while there is some additional conductivematerial apart from the loop 202 (i.e., the conductors 214 and 216), onits own, the near field only RFID tag 225 is only readable in the nearfield.

All of the near field only RFID tags of FIGS. 2A-2D are designed to onlybe readable in the near field of RFID communication. While the nearfield only RFID tags of FIGS. 2B-2D may be configured to operate and bereadable in the far field of RFID communication, this requires theadditional coupling of a far field antenna.

It is understood that the near field only tags 200, 205, 215, and 225may be designed to operate with reader antennas operating at a varietyof frequencies, such as low frequency (LF) at 125-134 kHz, highfrequency (HF) at 13.56 MHz, ultra high frequency (UHF) at 860-960 MHz,microwave frequencies at 2.4 and 5.8 GHz, for example.

Referring now to FIG. 3, an RFID based object tracking system 300 for amoving conveyor is shown. The system 300 includes a conveyor system 302having rollers 304, an object 306 being conveyed and including a nearfield only RFID tag 310, an RFID tag reader 308 (which may also bereferred to as an RFID-tag reader or simply as a reader), and a controlcircuit 312 coupled to the tag reader 308. As is well known in the art,the RFID reader 308 is configured to “read” any RFID tags (which mayalso be referred to as RFID transceivers), such as an RFID tag withinthe operating range of both the RFID reader 308 and the RFID tag. Insome embodiments, the reader 308 is a standard RFID tag reader that canread tags in both the near field and far field of RFID communications.

In accordance with several embodiments, the object 306 includes a nearfield only RFID tag (such as shown in FIGS. 2A-2D) that is applied tothe object, e.g., applied, adhered, attached, etc., to the object. Thereader 308 is positioned at the conveyor in order to read tags in a nearfield of RFID communication as they pass the reader 308. For example, asillustrated, the reader 308 is positioned underneath the conveyor pathbetween the rollers 304 of the conveyor system 302. As the object 306travels on the rollers 304, since the near field only RFID tag 310 isnot readable in the far field of RFID communication, the near field onlyRFID tag 310 will not respond to read signals from the reader 308 whenthe object is in the far field range of the reader 308. However, whenthe near field only RFID tag 310 enters the near field range 314 (e.g.,the near field radiating sub-region 104 and the near field reactivesub-region 106 of FIG. 1) of RFID communication of the reader 308, thenear field only RFID tag 310 responds to the read signals from thereader 308 and is read by the reader 308. In this case, the object tagis read only at close range 320 from the reader 308 such that the reader308 will only be able to read the near field only RFID tag of one objectat a time. By using near field only RFID tags 310 as opposed to thetraditional near/far field tags of the known approaches, the tags of theobjects being conveyed are read one at a time completely eliminating theproblems of the known approaches where objects may be read in the farfield out of order due to the dielectric properties of the objects.

The reader passes the read information to the control circuit 312 whichprocesses reads of the near field only RFID tags 310 by the RFID reader308 to determine an order of the objects being conveyed. In theseembodiments, the order of the objects moving on the conveyor system issimply the order that the near field only RFID tags 310 of the objectsare read. No additional processing involving evaluations of phase shift,signal strength, etc. is needed to filter other tags read by the reader308.

In some embodiments, the control circuit 312 receives an indication of aread time when a read response is received at the RFID reader 308 andthis read time information is used by the control circuit 312 todetermine the order of the objects on the moving conveyor. In someembodiments, the control circuit is part of a networked computer systemcoupled to the reader 308 and configured to identify and track theplurality of objects moving on the conveyor system. In some embodiments,the control circuit 312 automatically receives read responses from thereader 308 and automatically processes the read responses to determinean order of the plurality of objects being conveyed on the conveyorsystem.

FIG. 4 illustrates a system 400 that is a variation of the system 300 ofFIG. 3 wherein the conveyor system includes a conveyor belt 402 movingabout rollers 404. In these embodiments, the RFID reader 308 ispositioned underneath the conveyor belt 402 such that it can read thenear field only RFID tags 310 of the objects passing overhead on theconveyor belt 402. Other features of the system of FIG. 4 are similar tothose of FIG. 3 and are not discussed further.

In the systems of FIGS. 3 and 4, the objects each include a near fieldonly RFID tag associated therewith and that identifies the object. Insome cases, the near field only RFID tags 310 are encoded with anelectronic product code (EPC) to identify the object. Each near fieldonly RFID tag 310 is not coupled to a far field antenna; thus, it is notreadable in a far field of RFID communication and communicates only in anear field of RFID communication. In some embodiments, in order to beeasily read in the near field range 314 of the reader, the near fieldonly RFID tags 310 are proximate to (e.g., at or on) a bottom portion ofthe object. In some cases, the near field only RFID tag 310 is appliedto an exterior bottom surface of the object 306. In other cases, the tag310 is applied to an inner surface of the object 306. The objects 306each may a single item or may be a collection or package of items, ormay be a container containing multiple items, and so on. Items may beproducts intended to be sold to consumers and may have differingdielectric properties. When the object 306 itself is a container, thenear field only RFID tag uniquely identifies the container as acontainer of the item, e.g., a case pack encoded tag. In someembodiments, the items within a container may themselves includeidentifying RFID tags, such as traditional near field/far field tags.Container tags may be distinguishable from item tags, e.g., the IDs ofthe object/container tags include information so that the controlcircuit can determine that the read tag is a container. Since the nearfield only RFID tags may be easily read in order by the reader 308, theobjects may be objects of multiple different sizes and/or have multipledifferent dielectric characteristics. With the use of near field onlyRFID tags on the objects, the tracking system can reliably sequenceobjects traveling on the conveyor at typical distribution centerconveyor speeds, such as about 600 feet per second.

Referring next to FIGS. 5 and 6, side and top down view diagrams areshown of another RFID based object tracking system for a moving conveyorin accordance with several embodiments. In these embodiments, multipleobjects 306 are moving on the conveyor 502 that are to be sequenced. Inthese embodiments, the objects 306 are containers that themselvescontain one or more items, one or more of which include their ownidentifying RFID tags. As described above, each object includes a nearfield only RFID tag 310 which is read by the reader 308 when the nearfield only RFID tag passes within the near field range of the reader308. As described above, the reader 308 is coupled to the controlcircuit 312 which uses the read information to sequence the objects.

However, it may be more challenging to read the near field only RFIDtags 310 of the objects 306 when the items within the objects are taggedwith RFID tags. That is, the reader 308 will also read the tags of theitems within the objects. These RFID tags are conventional tags that maybe read in the near and far fields. Thus, the reader will be able toread many tags in the approaching objects 306. As the number of tags inthe read ranger increases, it is more difficult to process the readtags. A conventional reader can read about 200 tags per second, andconventional conveyors of distribution centers move very fast, e.g.,about 600 feet per second. It becomes more challenging to read andfilter the near field only RFID tag reads from the many other tags beingread at the same time. Thus, in some embodiments, it is desired to quiettags that not needed in the sequencing process. According, in someembodiments, an additional tag reader 506 is provided upstream relativeto the direction of movement from the reader 308. As shown, theadditional reader 506 is mounted on a support structure 504 and directedtoward the incoming objects 306. In some embodiments, the additionalreader 506 broadcasts signaling 510 to any RFID tags that are capable ofbe read or receiving signaling in the far field of RFOD communications.In the illustrated embodiment, the additional reader 506 is mounted highenough such that the near field only RFID tag 310 cannot respond to thesignaling. This signaling 510 is intended to attempt to transition theRFID tags of the items within the objects 306 to a non-readable stateprior to the objects 306 being conveyed into a far field read range ofthe RFID reader 308. For example, the signaling 510 includes read statechange command signals that cause any receiving RFID tag to transitionto the non-readable state in response thereto according to the RFIDcommunication protocol. In another example, the signaling 510 includesread signals to attempt to read the RFID tags of the items in theobjects 306 in the far field of RFID communications. Any receiving tagwill respond to the read signal and then transition to the non-readablestate. For example, tags encoded according to the Electronic ProductCode (EPC) Global Standard operating in inventory state session 2 or 3of the EPC Radio-Frequency Identity Protocols Class-1 Generation-2 UHFRFID Protocol for Communications at 860 MHz-960 MHz Version 1.0.9 (whichis incorporated herein by reference) will transition to a non-readablestate for a period of time until they lose power. During this period oftime, the RFID tag will not respond to read signals. The tag will thenlose power, and automatically return to a readable state. A typical tagwill stay quiet for about 10-15 seconds before losing power. In anyevent, based on the signaling 510, it is intended that the majority ifnot all RFID tags of the items contained within the objects aretransitioned to a non-readable state (the tags are “quieted”) prior toreaching the far field read range of the reader 308. Thus, when thereader 308 is attempting to read the near field only tags of the objects306, the reader 308 does not also read the RFID tags of the items (sincethey are quieted). In the event that one or more RFID tags are nottransitioned to the non-readable state when they reach the far fieldrange of the reader 308 and are read, the reader 308 and/or the controlcircuit 312 is configured to discard the tags reads that do not identifyan object 306 as a container of items. In some embodiments, multipleadditional readers 506 are positioned upstream from the reader 308 toincrease the likelihood that the RFID tags of the items are quieted. Inthe event that the signaling 510 includes read signals, the reader 506may or may not make use of the read tag IDs depending on whether theadditional reader 510 includes a purpose other than to quiet the itemtags that are readable in the far field. Thus, in some embodiments, thereader 506 discards or ignores read tag IDs.

In some embodiments, a distance 508 between the reader 308 and theadditional reader/s 510 about the conveyor path is determined such theRFID tags of the plurality of items contained within a given object willreceive the signaling from the additional RFID reader 510 prior to theRFID tags of the items being readable by the reader 308. This distance508 may be determined based at least on the speed of the conveyor systemand the duration of time that the quieted tags will remain quiet.

FIG. 7 illustrates one embodiment of a control circuit such as generallyshown in FIGS. 3-6. The control circuit 700 includes a processor 702, amemory 704, an input/output (I/O) interface 706 (e.g., a backendinterface) and an optional user interface 708 (e.g., a frontendinterface). Generally, the memory 704 stores the operational code or setof instructions that is executed by the processor 702 to implement thefunctionality of the control circuit. The memory 704 also stores anyparticular data that may be needed to make any of the determinationsdescribed herein. Such data may be pre-stored in the memory or bereceived, for example, from a central computer system (e.g., adistribution center or inventory management computer system) during use.It is understood that the processor 702 may be implemented as one ormore processor devices as are well known in the art. Similarly, thememory 704 may be implemented as one or more memory devices as are wellknown in the art, such as one or more processor readable and/or computerreadable media and can include volatile and/or nonvolatile media, suchas RAM, ROM, EEPROM, flash memory and/or other memory technology.Further, the memory 704 is shown as internal to the control circuit 700;however, the memory 704 can be internal, external or a combination ofinternal and external memory. Additionally, the control circuit mayinclude a power supply (not shown) or it may receive power from anexternal source.

The processor 702 and the memory 704 may be integrated together, such asin a microcontroller, application specification integrated circuit,field programmable gate array or other such device, or may be separatedevices coupled together. The I/O interface 706 allows communicationalcoupling of the control circuit to external components, such as acentral computer system and/or any user devices. Accordingly, the I/Ointerface 706 may include any known wired and/or wireless interfacingdevice, circuit and/or connecting device. In some embodiments, a userinterface 708 is included in the control circuit 700 which may be usedfor user input and/or output display. For example, the user interface708 may include any known input devices, such a buttons, knobs,selectors, switches, keys, touch input surfaces and/or displays, etc.Additionally, the user interface 708 may include one or more outputdisplay devices, such as lights, visual indicators, display screens,etc. to convey information to a user, such as any sequencing informationdetermined by the control circuit 700. The control circuit 700 isconfigured to communicate with the reader 308 to control its operationand to receive information from the RFID reader 308 regarding thereading of the near field only RFID tags 310 of the objects 306. WhileFIG. 7 illustrates the RFID reader 308 being coupled to the processor702, it is understood that the reader 308 may actually be coupled to acommunication bus of the control circuit 700 to which the processor 702and/or memory 704 may also be coupled.

In some embodiments, the control circuit 700 is integrated with or partof the device or apparatus including the RFID reader 308. In such cases,a function indicated herein as being performed by the control circuit700 may also be performed by the RFID reader 308. In other embodiments,the control circuit 700 is separate from and coupled to the RFID reader308. For example, the control circuit 312 may be located at, integratedinto or coupled to a central distribution center or inventory managementcomputer system. In such cases, the control circuit 700 is coupled tothe reader 308 by one or more wired and/or wireless communication linksusing the appropriate communicating devices.

Generally, the control circuits 312 and 700 can comprise a fixed-purposehard-wired platform or can comprise a partially or wholly programmableplatform. These architectural options are well known and understood inthe art and require no further description here. These control circuits312 and 700 are configured (for example, by using correspondingprogramming as will be well understood by those skilled in the art) tocarry out one or more of the steps, actions, and/or functions describedherein.

Referring next to FIG. 8, a flow diagram is shown of a method inaccordance with several embodiments to track objects moving on a movingconveyor system. One or more embodiments may be performed using one ormore of the systems, readers, and control circuits described herein.

Initially, a plurality of objects are transported along a conveyancepath of a conveyor system, wherein each object includes a near fieldonly RFID tag (e.g., near field only RFID tag 200, 205, 215, 225, 310)associated therewith and identifying the object (Step 802). Each nearfield only RFID tag is not coupled to a far field antenna such that itis not readable in a far field of RFID communication and communicatesonly in a near field of RFID communication. In some embodiments, thenear field only RFID tag uniquely identifies its corresponding object.In some embodiments, the near field only RFID tag of each object ispositioned at or proximate to a bottom surface of the object. In someembodiments, the objects have one or both of different sizes anddifferent dielectric characteristics.

Optional step 804 will be described after describing steps 806-810.Then, a first RFID tag reader (e.g., reader 308) positioned relative toa first portion of the conveyor system sends read signals to attempt toread the near field only RFID tag of each object (Step 806). In someembodiments, the first RFID tag reader is positioned underneath theconveyor system at the first portion of the conveyor system such thatthe near field only RFID tags will be able to respond to read signals inthe near field of RFID communication as the objects pass over the firstRFID reader.

Next, the first RFID reader receives responses from the near field onlyRFID tag of each object when the near field only RFID tag is within thenear field of RFID communications of the first RFID reader (Step 808).

Next, a control circuit receives information corresponding to the readtags and automatically processes the responses from the near field onlyRFID tags to determine an order of the objects being conveyed (Step810). Since the near field only RFID tags are only readable in the nearfield, the order of reading the objects indicates the order of theobjects on the conveyor. The information received from the reader mayinclude a read time indication to indicate the time at which the tag wasread. This read time information can be used in the processing by thecontrol circuit to determine the order or sequence of the objects.

In the event the objects are containers that contain one or more itemsthat themselves may be tagged with identifying RFID tags that may beread in the far field, optional step 804 may be performed. That is, oneor more additional RFID tag readers positioned upstream along the pathof conveyance relative to the first portion of the conveyor systemincluding the first reader, broadcast signals to the RFID tags of theitems in the far field to attempt to transition these RFID tags to anon-readable state prior to the objects being conveyed into a far fieldread range of the first RFID reader (Step 804). In some embodiments,this broadcast signaling attempts to quiet the items tags so that theydo not hinder the first tag reader's ability to read the near field onlyRFID tags of the objects. In some embodiments, the signaling includesread signals which will cause the receiving RFID tags to respond and goto a non-readable state for a period of time such as described herein.In other embodiments, the signaling includes read state change commandsignals that will cause the item tags to transition to the non-readablestate. If the additional readers are successful, most if not all of theitem RFID tags will be quieted when the objects reach the far fieldrange of the first RFID tag reader. In the event not all tags arequieted, the first RFID tag reader and/or the control circuit areconfigured to discard any read of the item tags. The positioning of theadditional readers relative to the first reader may be configured asdescribed herein.

In some embodiments, apparatuses and methods are provided herein usefulto track objects on a moving conveyor system. In some embodiments, anRFID based tracking system comprises: a conveyor system configured tomove and transport a plurality of objects along a conveyance path,wherein each of the plurality of objects includes a near field only RFIDtag associated therewith and identifying the object, wherein each nearfield only RFID tag is not coupled to a far field antenna such that itis not readable in a far field of RFID communication and communicatesonly in a near field of RFID communication; a first RFID tag readerpositioned relative to a first portion of the conveyor system andconfigured to attempt to read the near field only RFID tag of each ofthe plurality of objects; and a control circuit configured to processreads of the plurality of near field only RFID tags by the first RFIDreader to determine an order of the plurality of objects being conveyed.

In some embodiments, a method of method of tracking objects using radiofrequency identification (RFID) communications, the method comprises:transporting a plurality of objects along a conveyance path of aconveyor system, wherein each of the plurality of objects includes anear field only RFID tag associated therewith and identifying theobject, wherein each near field only RFID tag is not coupled to a farfield antenna such that it is not readable in a far field of RFIDcommunication and communicates only in a near field of RFIDcommunication; sending, by a first RFID tag reader positioned relativeto a first portion of the conveyor system, read signals to attempt toread the near field only RFID tag of each of the plurality of objects;receiving, by the first RFID reader, responses from the near field onlyRFID tag of each of the plurality of objects when the near field onlyRFID tag is within the near field of RFID communications of the firstRFID reader; and processing, by a control circuit, the responses fromthe plurality of near field only RFID tags to determine an order of theplurality of objects being conveyed.

In some embodiments, an apparatus and a corresponding method performedby the apparatus, comprises: a networked control circuit coupled to amemory device and configured to: automatically receive a read responsereceived at a first radio frequency identification (RFID) reader from anear field only RFID tag of each of a plurality of objects beingtransported by a conveyor system along a conveyance path, each nearfield only RFID tag associated with and identifying a given one of theplurality of objects, and each near field only RFID tag being notcoupled to a far field antenna such that it is not readable in a farfield of RFID communication and communicates only in a near field ofRFID communication, wherein the first RFID reader is positioned relativeto a first portion of the conveyor system in order that the near fieldonly RFID tag of each of the plurality of objects responds to a readsignal from the first RFID reader when the near field only RFID tag iswithin the near field of RFID communication of the first RFID reader;and automatically process the read response of each of the plurality ofobjects to determine an order of the plurality of objects being conveyedon the conveyor system.

Those skilled in the art will recognize that a wide variety of othermodifications, alterations, and combinations can also be made withrespect to the above described embodiments without departing from thescope of the invention, and that such modifications, alterations, andcombinations are to be viewed as being within the ambit of the inventiveconcept.

What is claimed is:
 1. A radio frequency identification (RFID) basedtracking system comprising: a conveyor system configured to move andtransport a plurality of objects along a conveyance path, wherein eachof the plurality of objects includes a near field only RFID tagassociated therewith and identifying the object, wherein each near fieldonly RFID tag is not coupled to a far field antenna such that it is notreadable in a far field of RFID communication and communicates only in anear field of RFID communication; a first RFID tag reader positionedrelative to a first portion of the conveyor system and configured toattempt to read the near field only RFID tag of each of the plurality ofobjects; and a control circuit configured to process reads of theplurality of near field only RFID tags by the first RFID reader todetermine an order of the plurality of objects being conveyed.
 2. Thesystem of claim 1 wherein each of the plurality of objects comprises acontainer containing a plurality of items therein, and each of theplurality of items includes an RFID tag associated therewith,identifying the item, and configured to be read in the near field andthe far field of RFID communication.
 3. The system of claim 2 furthercomprising: one or more additional RFID tag readers positioned relativeto a second portion of the conveyor system that is upstream along thepath of conveyance relative to the first portion of the conveyor systemand is configured to broadcast signaling to the RFID tag of each of theplurality of items in the far field of RFID communications to attempt totransition the RFID tags to a non-readable state prior to the objectsbeing conveyed into a far field read range of the first RFID reader. 4.The system of claim 3 wherein the one or more additional RFID tagreaders broadcast read signals to attempt to read the RFID tag of eachof the plurality of items in the far field of RFID communications, theRFID tag of each of the plurality of items being configured totransition to the non-readable state after responding to a read signal.5. The system of claim 3 wherein the one or more additional RFID tagreaders broadcast read state change command signals, the RFID tag ofeach of the plurality of items being configured to transition to thenon-readable state in response to receiving a read state change commandsignal.
 6. The system of claim 3 wherein the control circuit isconfigured to discard reads of any of the RFID tags of the plurality ofitems read by the first RFID reader.
 7. The system of claim 3 whereinthe second location and the first location of the conveyor system areseparated a distance, such that the RFID tags of the plurality of itemscontained within a given object will receive the signaling from the oneor more additional RFID readers prior to the RFID tags of the pluralityof items contained within the given object being readable by the firstRFID reader.
 8. The system of claim 1 wherein the first RFID reader isconfigured to read RFID tags in the near field of RFID communication andin the far field of RFID communication.
 9. The system of claim 1 whereineach near field only RFID tag uniquely identifies its corresponding oneof the plurality of objects.
 10. The system of claim 1 wherein the nearfield only RFID tag of each of the plurality of objects is positioned ator proximate to a bottom surface of the object.
 11. The system of claim1 wherein the first RFID tag reader is positioned underneath theconveyor system at the first portion of the conveyor system such thatthe near field only RFID tags will be able to respond to read signalsfrom the first RFID reader in the near field of RFID communication asthe plurality of objects pass over the first RFID reader.
 12. The systemof claim 1 wherein the plurality of objects comprise objects having oneor both of a plurality of different sizes and a plurality of differentdielectric characteristics.
 13. The system of claim 1 wherein thecontrol circuit is configured to: receive an indication of a read timewhen a read response is received at the first RFID reader from the nearfield only RFID tag of each of the plurality of objects; and process theindication of the read time and a read response of each of the pluralityof objects to determine the order of the plurality of objects beingconveyed.
 14. A method of tracking objects using radio frequencyidentification (RFID) communications, the method comprising:transporting a plurality of objects along a conveyance path of aconveyor system, wherein each of the plurality of objects includes anear field only RFID tag associated therewith and identifying theobject, wherein each near field only RFID tag is not coupled to a farfield antenna such that it is not readable in a far field of RFIDcommunication and communicates only in a near field of RFIDcommunication; sending, by a first RFID tag reader positioned relativeto a first portion of the conveyor system, read signals to attempt toread the near field only RFID tag of each of the plurality of objects;receiving, by the first RFID reader, responses from the near field onlyRFID tag of each of the plurality of objects when the near field onlyRFID tag is within the near field of RFID communications of the firstRFID reader; and processing, by a control circuit, the responses fromthe plurality of near field only RFID tags to determine an order of theplurality of objects being conveyed.
 15. The method of claim 14 whereineach of the plurality of objects comprises a container containing aplurality of items therein, and each of the plurality of items includesan RFID tag associated therewith, identifying the item and configured tobe read in the near field and the far field of RFID communication. 16.The method of claim 15 further comprising: broadcasting, by one or moreadditional RFID tag readers positioned relative to a second portion ofthe conveyor system that is upstream along the path of conveyancerelative to the first portion of the conveyor system, signals to theRFID tag of each of the plurality of items in the far field of RFIDcommunications to attempt to transition the RFID tags to a non-readablestate prior to the objects being conveyed into a far field read range ofthe first RFID reader.
 17. The method of claim 16 wherein the signalscomprise read signals to attempt to read the RFID tag of each of theplurality of items in the far field of RFID communications, wherein themethod further comprises transitioning the one or more RFID tags of theplurality of items to the non-readable state after responding to a readsignal.
 18. The method of claim 16 wherein the signals comprise readstate change command signals, the RFID tag of each of the plurality ofitems being configured to transition to the non-readable state inresponse to receiving a read state change command signal.
 19. The methodof claim 16 further comprising discarding, by the control circuit, readsof any of the RFID tags of the plurality of items read by the first RFIDreader.
 20. The method of claim 16 wherein the second location and thefirst location of the conveyor system are separated a distance, suchthat the RFID tags of the plurality of items contained within a givenobject will receive the signals from the one or more RFID readers priorto the RFID tags of the plurality of items contained within the givenobject being readable by the first RFID reader.
 21. The method of claim14 wherein the first RFID reader is configured to read RFID tags in thenear field of RFID communication and in the far field of RFIDcommunication.
 22. The method of claim 14 wherein each near field onlyRFID tag uniquely identifies its corresponding one of the plurality ofobjects.
 23. The method of claim 14 wherein the near field only RFID tagof each of the plurality of objects is positioned at or proximate to abottom surface of the object.
 24. The method of claim 14 wherein thefirst RFID tag reader is positioned underneath the conveyor system atthe first portion of the conveyor system such that the near field onlyRFID tags will be able to respond to read signals from the first RFIDreader in the near field of RFID communication as the plurality ofobjects pass over the first RFID reader.
 25. The method of claim 14wherein the plurality of objects comprise objects having one or both ofa plurality of different sizes and a plurality of different dielectriccharacteristics.
 26. The method of claim 14 further comprising:receiving, by the control circuit, an indication of a read time when aread response is received at the first RFID reader from the near fieldonly RFID tag of each of the plurality of objects; and wherein theprocessing step comprises processing, by the control circuit, theindication of the read time and a read response of each of the pluralityof objects to determine the order of the plurality of objects beingconveyed.
 27. An apparatus comprising: a networked control circuitcoupled to a memory device and configured to: automatically receive aread response received at a first radio frequency identification (RFID)reader from a near field only RFID tag of each of a plurality of objectsbeing transported by a conveyor system along a conveyance path, eachnear field only RFID tag associated with and identifying a given one ofthe plurality of objects, and each near field only RFID tag being notcoupled to a far field antenna such that it is not readable in a farfield of RFID communication and communicates only in a near field ofRFID communication, wherein the first RFID reader is positioned relativeto a first portion of the conveyor system in order that the near fieldonly RFID tag of each of the plurality of objects responds to a readsignal from the first RFID reader when the near field only RFID tag iswithin the near field of RFID communication of the first RFID reader;and automatically process the read response of each of the plurality ofobjects to determine an order of the plurality of objects being conveyedon the conveyor system.
 28. The apparatus of claim 27 wherein thenetworked control circuit is configured to: automatically receive anindication of a read time when the read response is received at thefirst RFID reader from the near field only RFID tag of each of theplurality of objects; and automatically process the indication of theread time and the read response of each of the plurality of objects todetermine the order of the plurality of objects being conveyed on theconveyor system.
 29. The system of claim 27 wherein each of theplurality of objects comprises a container containing a plurality ofitems therein, and each of the plurality of items includes an RFID tagassociated therewith and corresponding thereto, and wherein one or moreadditional RFID readers are used to broadcast signaling to attempt totransition the RFID tag of each of the plurality of items to anon-readable state before the first RFID reader can read the RFID tag ofeach of the plurality of items, and wherein the networked controlcircuit is configured to automatically discard reads of any of the RFIDtags of the plurality of items read by the first RFID reader that werenot transitioned to the non-readable state.
 30. A method comprising: bya networked control circuit coupled to a memory device, automaticallyreceiving a read response received at a first radio frequencyidentification (RFID) reader from a near field only RFID tag of each ofa plurality of objects being transported by a conveyor system along aconveyance path, each near field only RFID tag associated with andidentifying a given one of the plurality of objects, and each near fieldonly RFID tag being not coupled to a far field antenna such that it isnot readable in a far field of RFID communication and communicates onlyin a near field of RFID communication, wherein the first RFID reader ispositioned relative to a first portion of the conveyor system in orderthat the near field only RFID tag of each of the plurality of objectsresponds to a read signal from the first RFID reader when the near fieldonly RFID tag is within the near field of RFID communication of thefirst RFID reader; and automatically processing the read response ofeach of the plurality of objects to determine an order of the pluralityof objects being conveyed on the conveyor system.